Method of extraction or other countercurrent treatment



Aug. 9, 1932- .1. M. COAHRAN ,3

METHOD OF EXTRACTION OR OTHER COUNTERCURRENT TREATMENT Original FiledJan. 21, 1925 5 Sheets-Sheet l ii A7 A? M M, Qll M i 46 L5: :l I n "1/447in jnvmm":

Jase/fZ. LZ/Zfam 1 I I I Aug 9, 1932. M A 1,870,834

METHOD OF EXTRACTION OR OTHER COUNTERCURRENT TREATMENT Original FiledJan. 21, 1925 3 Sheets-Sheet 2 1932- J. M. COAHRAN 1,810,834

METHOD OF EXTRACTION OR OTHER COUNTERCURRENT TREATMENT Original Fi ledJan. 21, 1925 3 Sheets-Sheet 5 fwae ZZZ. 6210M.

Patented .Aug. 9, 1932 UNITED STATES PATENT ei-mice Jesse M. comm, orsmn'rnroar, PENNSYLVANIA, ASSIGNOR ro oLimN'sALns coa- PORATION, OFOLEAN, NEW YORK, CORPORATION OF DELAWARE METHOD EXTRACTION OR OTHERCOUNTEBCURRENT TREATMENT;

Original application filed January 21, 1925, Serial No. 3,797, nowPatent No. 1,845,128, dated February 16,

1932. Divided and this application filed March 16, 1927. Serial No.175,734.

This invention relates to method of counfrom the solvent, however,present opposed tercurrent flow treatment having been develconditions,and as eretofore practiced this oped more particularly for theextraction of eneral method of ecovery of chemicals has chemicals frommaterial containing them can carried out as a compromise, balancing 6through the use of solvents for the chemicals. the wastage of chemicalsthrough incomplete The solvent is brought into intimate contactextraction against the saving effected by rewith the material containingthe chemicals,icovery from the more highly saturated solwhereby thematerial yields a portion of the en chemicals to the solvent which isthen re- According'to the present invention, how- 10 moved and thechemicals recovered thereever both of these apparently inconsistentfrom. In order that the largest possible proconditions are maintained inthe one apparaportion of chemicals shall be removed from tus, and in acontinuous counter flow process, the material it is evident that arelatively a relatively large or preponderating volume small quantity ofmaterial should be treated of the solvent contacting with arelativelywith a relatively large quantity of solvent, small volume of nearlyextracted material, and also that for the most efficient extraction, andthe major portion of the extractionbeing material from which thechemicals have been efi'ected with a large proportion of solvent to morenearlyremoved should be treated with material so that the extractionmaybe highly the fresher solvent. The use ofa relatively efiicient, andthe more nearly saturated sol- 2 large amount of solvent for the totalamount vent being thereafte brought into intimate of material treated,and consequently for the contact with a relatively large or preponderamount of chemicals recovered, would,-howating volume of substantiallyuntreated mateever, result in a large amount of solvent solurial inorder that the concentration in the soltion weak in chemicals from whichthe chemventat the end of the treatment shall be, icals would berecovered. This would greatly high, thus requiring the minimum amount ofincrease the difiiculties and the cost of such treatment for recovery ofthe chemicals from recovery due to the great volume handled in thesolvent. pro ortion to the amount of chemicals recov- In my Patent No.1,845,128 granted Febru ere For the most efiicient recovery, thereary16, 1932, for apparatus for extracting fore, it is desirable that thechemicals should chemicals from liquors is disclosed an be highlyconcentrated in the solvent. To 'claimed an apparatus for carrying outthe effect this, it is clear that a relatively small method thereinclaimed as ap lied to extracamount of solvent must be used to-treat ation of chemicals from liqui s, the present relatively large amount ofmaterial and that application covering matter divided out from materialcontaining the greatest portion of also to extract from solids or anyuent mashsmicals to be extracted teria-l of such a nature as to beeasily sepa- The treatment f h n y exhausted -Qrated from the solventand in its broadest tenal with the fresh solvent and the freshgaspectsmay be found applicable to any counmaterial with the more nearlysaturated soltercurrent flow treatment. An apparatus invent may bereadily effected by e li hing tended for extraction from fluent solidmateflow of the material and solvent in opposite rial according to themethod of this invendirections while in contact with each other. tion isdisclosed and claimed in my Patent No. The treatment of arelativelysmall amount 1,793,465 t d F b ar 24, 1931, for of material with arelatively large amount of th d fi m f l hi g. solvent for mosteflicient extraction, and the Where the material to be extrac e is oftreatment of a relatively small amount of different specific gravityfrom the solvent, solvent with a relatively large amount of maadvantagemay be taken of this diif'erence in terial for the easiest recovery ofchemicals specific gravity to cause automatic separation the solventmore nearly saturated with the that application. This method is notlimitedv chemicals shouldbebrought into contact with to extraction fromIiquidsbut ma be used 10 For a more complete understanding of thisinvention, reference may be had to the accompan ing drawings in whichone embodiinent an apparatus capable-of carrying out the improvedprocesses applied to extraction of chemicals from liquors is set forth.While theinvention will be described with more particular reference toextraction of chemicals from liquors moreparticularly the extraction ofacetic acid from pyroligneous l acid liquor, it should be understoodthatin its broader aspects it is not limited to such use, but isapplicableto treatment of any material with a-treatin agent to produce aphysical interchange t erebetween where the material and agent may becaused to move in countercurrent flow and where the material and agentmay be readily separated after the treatment has been effected. Itshould be evident, however, that the process might be carried out inother apparatus differing in many respects from that illustrated.

Referring to the accompanying drawings: Figure 1 i's a side elevation ofthe extractor. Figure-2. is a vertical cross section through an uppersection thereof.

Figure 3 is a vertical cross section through one of the intermediatesections.

Figure 4 is a vertical cross section throughthe lowest section.

Figure 5 is a horizontal cross section on line 55 of Figure 3.

Figure 6 is a detail section Figure 5. V

Figure? is adetail section to an enlarged scale of the upper shaftbearing and related parts.

' Figure 8 is a section on either of the lines 8-8 of Figure 1.

Figure 9 's a section on line 9-9 of Figure 8.

Figure 10 is a fragmentary view similar to a portion of Figure 8, butshowing the parts in difierent positions.

' Referring to Figure 1, it will be seen that the extractor comprises aplurality of superposed sections forming together a column in which thesolvent and the liquor are brought into intimate contact while flowingin oppo site directions. As shown, this column comprises four sectionsalthough more orless might be employed to suit the particular conditionsin any given case. As shown, howon line 66 of ever, there is a lowersection 1, a pair of'incal position on a suitable foundation 5. Thesecolumn sections should, of course, be made of material which is notdeleteriously affected by the liquor or saturant employed, or should belinedwith some material having this char acteristic.

. Referring more particularly to Figures 2 and 7, it will be noted thatthe upper section 4 is closed off at its upper end by means of a topplate 10, through the center of which passes the section 11 of a shaftaxially arranged in the column; this shaft 11 extending through astufling box 12. At 13 is shown an inverted U shaped bracket forsupporting above the plate 10 a thrust bearing 14 which is designed totake the Weight of the shaft and the parts carried thereby, as willlater appear and to permit free rotation thereof.

As shown best in Figure 7, the shaft section.

11 is tubular and above the plate 10 it has inserted therein the lowerend of the solid shaft section 15 pinned thereto by a transverse pin 16.This shaft section 15 extends through a ball-bearing 17, and above thisball-bearing it is keyed within a sleeve 18 which carries a plurality ofrollers 19 engaging between hardened disks 20 and 21 seated within acounterbored portion 22 of the bearing member 23. A sleeve 25 having anoutwardly extending flange 26 termi ating in a downwardly extendingskirt 27, 1s fixed to the shaft section 15 above the bearing 14, theskirt 27 enclosing the upper end of this bearing member 23. To thissleeve25 is fixed any suitable means for rotating the shaft, as shown abelt pulley 30 being used for this purpose. The axial position of theshaft through this thrust bearing may be adjusted by means of a nut 31threaded on the shaft section 15 above the sleeve 25 and a check-nut 32positioned thereabove may be used in order to lock the nut 31 inadjusted position.

The shaft section 11 extends through. the column section 4. and at itslower end is fixed therein a plug having a threaded lower end 41 bywhich it may be attachedto a shaft section in the upper intermediatesection 3, as will later appear. Within thelower portion of the columnsection 4 is fixedin vertical spaced relation a series of flatimperforated annular baffle plates 45. As shown these bafseries to anannular angle member. 47 riveted or otherwise fixed. to the inner faceof the column section4, the bafiie plates being in spaced relation onthe shaft 11. Itwill be noted that the upper rotating baffle plate ispositioned considerably below the top-plate 10 of the column section,thus leavinga-subfie plates are strung upon tie-bolts or rods 46, madefast at their lower ends in circular Somewhat above the upper rotatingbe e 50,

is positioned an inlet-pipe 55 provided witha valve 56, and somewhatabove this pipe is positioned an outlet pipe 57 provided with aregulating valve 58. It will be noted that the inlet pipe 55 extendswell into section 4, so as to discharge against the'shaft section 11 inorder that the fluid may be deflected thereby and be spread somewhatover the cross sectional area of the upper section 4. The outlet pipe 57may also extend well within the section 4 as withdrawing solvent fromthe center of the column aids in producing symmetrical flow of liquidsin the column.

Below the section 4 is an intermediate section 3 shown in detail inFigures 3, 5. and 6.

iVithin this section-and throughout substantially its entire length arealternate series of fixed bafiies 60, and rotating bafiies 61. The

rotating bafiies 61 are carried by a vertical hollow shaft 65 having atits upper end a threaded opening 650 to receive the threaded lower end41 of the plug carried by the tubular shaft section 11 by which meansthis section 11 may be firmly attached to the shaft section 65 so thatboth'may' rotate together. The stationary baffles 60 are carried bytierods 66, supported at their lower ends in'an annular angle member 67fixed to the wall of the section 3, these stationary bafiies be ingspaced apart along the tie-rods by spacing sleeves 68 similar to thespacing sleeves 48 in the upper section 4. It will thus be seen that themounting of the stationary baffles is the same in the two sections, butin section 3 the series of rotating and stationary baffles extend thewhole length of the section, whereas in the upper section 4 theterminate well below its upper end and be ow the intake pipe '55. W p

In Figures 5 and 6, is shown indetail the manner'of attaching'therotating baflles to the shafts 11 and 65 and their construction.

Each of these rotary baflies comprises a sub stantially flat disk 70having a downwardly turned outer stiffening margm'71, and a cen tralperforation having anupwardly extending margin 72. This upwardlyextending margin 72 is fixed to the outer face of a sleeve 73 throughwhich the shaftsection 11. or65k passes, this sleeve 7 3 being fixed tothe shaft by means of a transverse bolt 74 passin through matingperforations in the shaft an sleeve. Except for the central 0 enings to.

receive the actuating shaft these. files are imperforate. For a purposewhich will later appear, there are provided radially extending fins 75and 76 on the upper and lower faces of the disks 70, these fins beingpreferably arranged in staggered relation on their upper and lowerfaces. Similarly each of the stationary baflles is provided withradially extending fins 77 and 78 on its uper and lower faces, and itsinner edge may e provided with a stiffening flange similar to the flange71 of the rotary baflies. If

desired, both these baflies may be cast from suitable metal with disks,fins and hubs comsimilar to the upper section 4, but contains in itsupper portion only a series of station ary annular bafilcs 80 similarinall respects to the ba-flies 45 in the upper section, and rotatinbafiies 81 similar in all respects to the ba cs 50 in the upper section.The rotary battles are fixed to a hollow shaft 82 coupled to the lowerend of'the shaft section 65 in the. adjacent intermediate section 2 bymeans of a plug 40 fixed in such upper shaft section and havin athreaded lower end 41 for engagement within the upper end of the shaftsection 82. As shown the stationary baflies terminate substantially halfway down in this section while there are two rotary baffies 81 beneaththe lowest stationary baffle.

parts, this socket being in the upper end of a hollow post, 86 which hasa threaded connection at its lower end in a socket 87 fixed to the base88 of the column section 1. Beneath the lower rotating bafile 81' in thelower section 1, is shown a supply ipe 120 providedwith a control valve121 w lch-pipeextends well into the column section to discharge itscontents against the shaft section 82 to be deflected thereby so as toreach substantially the entire cross sectional area of the. column.Beneath this inlet pipe is an outlet pipe 122. provided with a valve123, this pipe extending well inside the column in the same manner asthe outlet pipe 57 at the upper-fend of the column.

The. central shaft is madeup in sections as shown, in order tofacilitate the assembling of the parts and during such assembly the post86' is ad'usted by screwingwupwardly 1n the socket 8 so that'its upperend is somewhat above the position which it is to take when the aparatus is in operation. The

section 82.w 1th the two lower rotary baflies 81 fixed thereon is thenplaced in position and the lowest stationary baflie 80 is then inserted.The next rotary bafile is fixed to the shaft 82, and then the nextstationary bafile 80 is placed in position, and so on until the rotaryand stationary. bafiles are com pletely. assembled in the lower section.The upper stationary baflle 80 of this section is provided with a shaftbearing 89, supported by radially arranged arms 890 extending inas inthe lower section 1. However, for a purpose which will later appear'aflow regulating device such as an iris diaphragm is preferably placedtoward the ends of the series of fixed and movable plates.

In the embodiment shown, these diaphragms are placed for convenience atthelower and upper ends of the lower and upper intermediate sections 2and 3. It is not always necessary to use such flow regulating devicesbut they increase the facility with which the flow of the solvent andliquor may be controlled. As shown best in Figures 8, 9 and 10, each ofthese diaphragms comprises a series of arc-shaped plates, 90, eachpivoted adjacent to one end as at 91 to an annular plate 92 placedbetween the flanged end 93 of the intermediate section and an annularcover plate 94 forming the adjacent end wall of the adjacent endsection, which sections as shown, are of larger diameter than theintermediate sections. I

Against the opposite faces of each of these plates is positioned anannular plate or ring 95, which is held in position with capa} bility ofrotating about its axis by means such as angle members 96 extendinginwardly from the wall of the corresponding interme- This ring isprovided with diate section. a series of inclined slots 97 in which ridepins 98 extending from the plates 90. By rotation of the ring 95 it isevident that the sections 90 will be rocked about their pivots 91 sothat their inner endsare caused to approach or recede from the-shaft 65,the inner ends of' these sections together defining a substantiallycircular opening through which the shaft passes. In the position shownin running of the shaft may be.-,insured.

post 86 throu h handholes at and the post screwed ownwardly into thesocket ;87 so that the weight of-the shaft and rotating baflles issupported entirely .by the roller thrust heating at the upper end of thecolumn which may run in an oil bath so that free For a more completeunderstanding of this invention it will be described in connection withthe recovery of acetic acid from 75 pyroligneous acid liquor, though 'itshould beunderstood that neither the method nor the apparatus is limitedto the recover of any particular chemicals. A solvent w ich isparticularly suitable for use in the repipe and outlet pipe 57hereinbefore referred to by proper adjustment of the valves in thesepipes. The position of the level of this liquid may be readilyascertained, forthis purpose a gagesglass being shown extendingverticallybetween the levels of these two pipes .in the upper columnsection 4'. The 95 upper portion of this column section forms asubstantially unobstructed chamber so that there is a body or pool ofconsiderable volume of acid liquor maintained therein from which aportion passes through the restricted pas-" sage between. the rotatingand stationary baflies in a tortuous zigzag course down through thelower portion of the column section 4, the sections 3 and 2, and theupper pore tion of column section 1. The ether is passed 1 through thepipe 120 into the lower column section 1 beneath the bafiies, and sincethe lower portion of this lower section is substantially unobstructedit. forms a bOdYjQr poplof considerable volume therein. From 11.

Figure 1, the elements 90 are rocked into sub-wthi s 'pool the etherpasses upwardly about the stantial contact with the shaft 65, so as toclose off therewithsubstantially the entire cross sectional area of theintermediate column section, while in Figure 10 they are rocked abouttheiraxes 91 in position to expose a relatively large opening betweentheir inner edges and the shaft 65. In order to rotate the ring 95, itis shown as having fixed thereto a segmental rack 100 with which nTay beturned. If desired this shaft 102 may b'e'supported in a bearin 105fixed-to the annular section. 7

After the column has been built up in the manner described access may behad to the plate 94 of the adjacent column end' alternatejtationary androtating baflles in zigzag course-contacting with the downwardly flowingacid liquor. As it is of less specific gravity than the acid'liquor, theacid liquor passes downwardly and the ether upwardly until the etherpasses above the uppermost baffles in column section 4. It then passesthrough the relatively large body or pool. of acidli' uor which has justbeen introduced through 1: e pipe 55 and is the most highly concentratedliquor, and the flow of ether 'up through this pool is "relatively slow,so that a relatively small quantity of ether having a considerablequantity of acetic acid in solution taken from the acid liquor withwhich it has previously been in contact passes through a relatively lare volume of highly concentrated liquor sot at the acid content of theethermay become as highly concentrated aspossible. This ether assumes aposition above the level of the body'or pool of acid liquor, as at thedotted line a-a of Figure 1, and is drawn off through the tpipe 57 andthe acid recovered therefrom y subjecting the acid-laden ether todistillation. The acid liquor passing downwardly through the column incontact with theupwardly flowing ether parts with some of its acid tothe ether so that as it reaches the lower portion of the column itbecomes relatively 1 weak ich is freer in acid. At the same time theether w remove acid from the acid liquor wherever the two are incontact. When the acid liquor reaches the lower portion'of the lowercolumn section 1 below the stationary baffles, it iscaused to passcomparatively slowly through a relatively large volume of fresh etherintroduced through the pipe 120 and which is maintained in the body orpool beneath the bafiies so that nearly all the then remaining acid isremoved therefrom. The liquor passing through this body or pool collectsat the bottom'of the column sectlon 1, and isdfawn off through the pipe123, the level of this spent liquor being maintained between the pipes120 and 122 substantiallyat the dotted line position b--b. The gageglass 141 at the lower portion of the column section 1 makes possiblethe determination of the level ofthe spent liquor which in turn definesthe lower limit of the pool of fresh ether through which the nearlyspent acid-liquor passes on its way to the outletpipe 122.

- The presence of the baflies insures a restricted passage between theupper pool of fresh liquor in the upper column section 4 and the owerpool of fresh ether in the lower column section 1 so that the amount ofthe acid passing downwardly ,is, relatively small in proportion to theamqunt of ether in the lower pool, and the amount of etherpassingupwardly is relatively small in proportion to the pool of fresh liquorin the up per column section 4. To further control the rate of flow ofthe acid-1i uor downwardly, and of the ether upward y, the diaphragmsbetween the upper and ower and the intermediate sections have been ed,and by adjustment of these diap ragms the proportions of ether toacid-liquor; in

their flow through the baflied section may be adjusted. For example, ifthe upper .dia-

phragm is closed more than the lower diaphragm, the fluid beneath the uper diaphragm will be largely ether, while if the 1 wer dia hra is. morenearl closed the 0 p gm y ity. and direction of flow, but also to theprefluid above it will largely acid-liquor.

In, order to increase-the size of the bodies or pools of fresh liquorand fresh ether relative to their rates of flow through each other, theupper .and'lower column sections have been shown as of larger diameterthan the rovidintermediate sections, this to increase theircross-sectional area, although the same result might be attained to alesser degree if all the sections were of the same diameter. Not only isthe passage between the upper and lower pools restricted by the baflies,but the rates and directions of flow of fluids about these baflies isconstantly changin while they are being mixed and agitated thereby; forexample, as the fluids pass to ward the central shaft, they flow towardthe center of the column and due to the fact that the cross'sectionalarea between the baffles is constantly decreasing as the central axis ofthe column is approached, the rate of flow is increased, sincethe samequantity of fluid flows throughout, while as the fluids pass by theinner ends of the stationary baffies they immediately flow outwardlytoward the periphery of the column in reverse direction to their formerflow and at constantly decreasing velocity due to the conlv by therotation so as tobe brought into contact with pan-shaped receptacles ofadiacent stationary baflies angularly disposed from those from which thefluid was received by the rotary baffles. The rotary baffles in thechambers at the ends of the columns beyond the stationary baflies act asstirrers to eflect an intimate mixture of the liquor and solvents in thepools. These baflies might. therefore, be formed with perforations overtheir surfaces distributed so a as to distribute the fluid emerging fromthe restricted passage evenlv over the cross sectional area of the poolor alternate pan sect ons between adiacentfins may be cut away, the cutaway portions of adiacent and rotary hel s, to mix the fluids gently soas not to disturb their gravity separations in the pools and causes themto pass in' diffused oondition through the pools.

vention of flow currents substantially axially of the column because ofthe" presence of the fins on theebafiies' which insure .circulation ofthe two'fluids spirally within the col 7 umn, though the tie rods 46 and66 offer ab- 'baflies being staggered. 1 This construction of chemicallyladen solvent with a relatively lower ends of each pool 1s very chiefvalues of these pools residing in the large quantity of fresh chemicalcontaining liquor has been effected, so that .the' spent liquor containsthe minimum amount of unrecovered chemicals which pass to waste and thesolvent is the most nearly saturated with chemicals that can be producedby the liquor of the degree of concentration treated by the apparatus.'While, as shown, the treatments,

in the upper and lower pools are countercurrent the extracting advantagederived directly therefrom is relatively unimportant because thedifi'erences in concentration of the chemicals being extracted at theupper and small, the

volumetric ratio at which extraction is "effected. The countercurrentflow in the upper I and lower pools does, however, have the importantfunction of insuring the maximum concentration of chemical to beextracted in the upper pool and the maximum strength of solvent in thelower pool throughout the entire. time of extraction. The process,therefore, may be said in general to consist of a countercurrentextraction, as between the end pools, and by which the most of the ex-'traction is effected, together with two additional extracting steps deending for their value on the volumetric re ation of material andsolvent during extraction with maximum purity of solvent in one instanceand minimum concentration of chemical in the other, and by one of whichthe efliciency of extrac' tion is increased and by the other of whichthe concentration of chemicals in the solvent is brought up close to itsmaximum. Of

course either of these additional steps could be omitted in case theend'attainedthereb might be relatively unim ortant, althoug both mayusually be realize without any very material complications of apparatus..The countercurrent flow treatment between the extractions effected inthe end pools is essentially a series of extractions each merging intothe next in opposite directions through the column so that the entireprocess with either one or both of the pools is a successivecountercurrent extraction with a progressively decreasing volumetricratio between solvent and .material as the extraction with the solventproceeds. One such decrease is from the large pool of fresh solvent atthe bottom of the column tov the central countercurrent flow portion,and another such dethat there appears to be no danger of emulthrough andin intimate contact with said maportion of such chemicals.

crease is from the central countercurrent flow portion to the upperpool. The levels of the liquor and solvent in the up er and lowersections of the column may be ept at the proper point by manipulation ofthe valves in the supply and outlet pipes therefor, as well as bymanipulation of the diaphragms by means of the hand wheels 104 and thespeed of rotation of the rotary baflies may be adjusted to that pointwhich is found mostsuitable for the particular fluids being treated.Where there is danger of emulsification of the liquids, of course, therotary bafiles should be rotated at such low speed that theemulsification does not take place. It has been found in practicesification occurring in the case of pyroligneous acid liquor and ther.

From the foregoing description of the method of this invention andcertain apparatus by which it may be performed it should. be evident-tothose skilled in the art that various'changes and modifications might bemade without departing from the spirit or scope of this invention asdefined by the appended -claims. I claim i I 1. The method ofacting onmaterial with a lishing countercurrent flow between said ma- 4 terialand agent while maintaininga prepon-' derating proportion ofsubstantially fresh treating agent to act on the more completely treatedmaterial and 'a prepon'derating pro portion of substantially untrealtedmaterial to act on the more completely used. treating agent.

2. The method of acting on material with treating agent to produce a.physical inter 7 change therebetween, which comprises estaba treatingagent to produce a physicalinter- 1 change therebetween, which comprisesestab- .lishing'continuous countercurrent flow between said material andagent while maintaining a larger volumetric ratio of treating agent tomaterial treated toward the end of the treatment of such material thanduring the earlier portion of said treatment.

3. The method of extracting chemicals from material which comprisespassing terial a solvent of suchchemicals in such a manner that a largeproportion of fresh solvent comes into contact with material weak inchemicals and as it takes up chemicals progressively contacts withmaterial containing a greater\proportion of such chemicals and finallycontacts with a relatively large proportion of material having a stillgreater pro- 4. The method. of extracting chemicals. from a material bythe use of a solvent for such chemicals which comprises maintaining arelatively large body of such material, maintaining a relatively largebody of such solvent, and maintaining a relatively material reachingsaid body of solvent and relatively free from chem1cals passes intointimate contact with a large volume of fresh solvent and the solventreaching said body of material and containing chemicals passes throughalarge volume of substantially untreated material.

5. The method of extracting chemicals from a liquor by the use of asolvent for such chemicals immiscible with such liquor which comprisesflowing such material and solvent in intimate contact with each other inopposite directions, and causing the material at the last portion of itscontact with the solvent to contact with a relatively large volume ofsubstantially fresh solvent, and causing the solvent at the last portionof its contact with the material to contact with a relatively largevolume of substantially untreated material.

6. The method of extracting chemicals, from a liquor which comprisespassing through and in intimate contact with said liquor a solvent ofsuch chemicals immiscible with the liquor in such a manner that a largeproportion of fresh solvent comes into contact with liquor weak inchemicals and as it takes up chemicals progressively contacts withliquor containing a greater proportion of such chemicals and finallycontacts with a relatively large proportion "of fresh liquor.

7. The method of extracting chemicals from a liquor by the use of asolvent for such chemicals immiscible with such liquor which comprisesmaintaining a relatively large pool of such liquor, maintaining arelatively large pool of such solvent, and maintaining a relativelysmall flow of liquor to and throughsaid pool of solvent, anda relativelysmall flow of solvent through and in intimate contact with said flow ofliquor to and through said pool of liquor, whereby the liquor reachingsaid pool of solvent and relatively free from chemicals passes intointimate contact with a large body of fresh solvent and the solventreaching said pool of liquor and containing chemicals passes through alarge body of fresh liquor.

8. The method of extracting chemicals from a liquor by the use of asolvent for such chemicals immiscible with such liquor which comprisesflowing such liquor and solvent in intimate contact with each other inopposite directions, and causing the liquor at the last the liquor tocontact with a relatively large,

volume of substantially fresh liquor.

9. The method of extracting chemicals from liquor by means of a fluidsolvent for such chemicals immiscible with the liquor and of differentspecific gravity which comprises maintaining in elevated position a poolof the heavier fluid, maintaining in a lower position a pool of thelighter fluid, permitting a-relatively small flow of the heavier fluidfrom said elevated pool downwardly and vdown through and in intimatecontact with the lighter fluid in the lower pool and drawing off theheavier fluid from beneath the; li hterfiuid in said lower pool, andpermitting a relativelysmall flow of said lighter fluid upwardly inintimate contact with said .a pool of the lighter fluid, permitting arelatively small flow of the heavier fluid from said I elevated pooldownwardly and down through and in intimate contact with the lighterfluid in the lower pool and drawing off the heavier fluid from beneaththe lighter fluid in said lower pool, and permitting a relatively smallflow of said lighter fluid upwardly in intimate contact with said flowof heavier fluid and up throughand in intimate contact with the heavierfluid in said elevated pool, drawing ofl said lighter fluid abovethelevel of the heavier fluid in said elevated pool, and varying thedirection and velocity of flow ot'said contacting fluids during theirflow between said pools.

11. The method of extracting acetic acid from acid containing liquor,which comprises maintaining a relatively large pool of such liquor,maintaining a relatively large pool of a solvent for acetic acidimmiscible with the liquor, establishing a relatively small flow ofliquor from said pool= of liquor to and through the pool of solvent andin intimate contact therewith, and maintaining a relatively small flowof solvent from said pool of solvent and in intimate contact with and inopposite direction to said flow of liquor and then through said pool ofliquor and in in timate contact therewith, drawing oil the spent liquorfrom'said pool of solvent, and drawing off the acetic acid ladensolvent-from said pool of liquor.

12.; The method of extracting chemicals from material which comprisesestablishing continuous counter flow in intimate contact of material anda solventfor such chemicals in a manner to increase substantially therelative proportionsof solvent to material in conno v tact with eachother as the material parts ratio of solvent to material than duringsuch countercurrent flow.

In testimony whereof I have affixed my with its chemicals to suchsolvents.

13. The method of extracting chemicals from a liquor containing suchchemicals,

which comprises flowing such liquor counter-- current to a solvent forsuch chemicals immiscible with such liquor and of difierent specificgravity, agitating such liquor and solvent While in contact with eachother, passing in diifused condition solvent containing extractedchemicals through a relatively larger volume of substantially freshliquor, passing nearly extracted liquor in diffused condition through arelatively larger volume of substantially fresh solvent, permittinggravity separation of such solvent with chemicals and extracted liquorfrom said pools respectively, and then drawing off the solvent with itschemicals and drawing off the extracted liquor.

' 14. The method of extracting chemicals from material containing suchchemicals, which comprises successively extracting the .materi'al with asolvent of such chemicals,

using progressively decreasing volumetric ratios between solvent andmaterial as the chemical content of such solvent increases.

15. The method of extracting chemicals from material containing suchchemlcals,

which comprises establishing countercurrent flow between such materialand a solvent of such chemicals at a predetermined volumetric ratio, andtreating the extracted material after suchflow to extraction bysubstantially fresh solvent at a substantially larger volumetric ratioof solvent to material than in said countercurrent flow.

signature.

from material containing such chemicals, i

which comprises establishing countercurrent flow between such materialand a solvent of such chemicals at a predetermined volumetric ratio ofmaterial and solvent, and thereafter extracting'more of suchmaterial-with the same solvent at a substantially larger volumetricratio of material to solvent than durmg such countercurrent flow, andtreating the material extracted during such countercurrent flow toextraction by substantially fresh solvent at a substantially largervolumetric CERTIFICATE or commcnon;

Patent No. 1,870,834.

' JESSE M. COAHRAN.

It is hereby certified that the above numbered patent was erroneouslyissued to "Olean Sales Corporation, of Olean, New York, a corporation ofDelaware", as assignee of the entire interestin said invention, whereassaid patent should August 1932.

have been issued to the inventor, said Jesse M. Coahran, sole owner ofsaid in- I vention; and that the said Letters Patent should beread withthis correction therein that the same may conform. to the record of thecase in the Patent Office.

Signed and sealed this 25th day of October, A, D. 1932.

' M. J. Moore,

(Seal) Acting Commissioner of Patents.

